Add information specifying the CPU core where timer callbacks (events)
were executed to the output of /proc/timer_stats.
Signed-off-by: Daniel Sangorrin <daniel.sangorrin@xxxxxxxxxxxxx>
Signed-off-by: Yoshitake Kobayashi <yoshitake.kobayashi@xxxxxxxxxxxxx>
---
Documentation/timers/timer_stats.txt | 41 ++++++++++++++++++++----------------
kernel/time/timer_stats.c | 20 ++++++++++--------
2 files changed, 34 insertions(+), 27 deletions(-)
diff --git a/Documentation/timers/timer_stats.txt b/Documentation/timers/timer_stats.txt
index 8abd40b..e54077a 100644
--- a/Documentation/timers/timer_stats.txt
+++ b/Documentation/timers/timer_stats.txt
@@ -21,7 +21,7 @@ Linux system over a sample period:
- the name of the process which initialized the timer
- the function where the timer was initialized
- the callback function which is associated to the timer
-- the number of events (callbacks)
+- the number of events (callbacks) executed per core
timer_stats adds an entry to /proc: /proc/timer_stats
@@ -45,23 +45,28 @@ readouts.
Sample output of /proc/timer_stats:
-Timerstats sample period: 3.888770 s
- 12, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick)
- 15, 1 swapper hcd_submit_urb (rh_timer_func)
- 4, 959 kedac schedule_timeout (process_timeout)
- 1, 0 swapper page_writeback_init (wb_timer_fn)
- 28, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick)
- 22, 2948 IRQ 4 tty_flip_buffer_push (delayed_work_timer_fn)
- 3, 3100 bash schedule_timeout (process_timeout)
- 1, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
- 1, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
- 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
- 1, 2292 ip __netdev_watchdog_up (dev_watchdog)
- 1, 23 events/1 do_cache_clean (delayed_work_timer_fn)
-90 total events, 30.0 events/sec
-
-The first column is the number of events, the second column the pid, the third
-column is the name of the process. The forth column shows the function which
+Timer Stats Version: v0.3
+Sample period: 4.365 s
+Collection: inactive
+ 0, 4366, 0 swapper/1 tick_setup_sched_timer (tick_sched_timer)
+ 4366, 0, 1 swapper/0 tick_setup_sched_timer (tick_sched_timer)
+ 0, 5, 1132 sshd sk_reset_timer (tcp_write_timer)
+ 0, 4, 515 apache2 schedule_hrtimeout_range_clock (hrtimer_wakeup)
+ 16, 0, 0 swapper/0 usb_hcd_poll_rh_status (rh_timer_func)
+ 16, 0, 0 swapper/0 usb_hcd_poll_rh_status (rh_timer_func)
+ 16, 0, 0 swapper/0 usb_hcd_poll_rh_status (rh_timer_func)
+ 16, 0, 0 swapper/0 usb_hcd_poll_rh_status (rh_timer_func)
+ 16, 0, 0 swapper/0 usb_hcd_poll_rh_status (rh_timer_func)
+ 0, 7, 0 swapper/1 sk_reset_timer (tcp_delack_timer)
+ 3, 4, 0 swapper/0 clocksource_watchdog (clocksource_watchdog)
+ 0D, 3D, 13 kworker/1:0 queue_delayed_work_on (delayed_work_timer_fn)
+ 3D, 0D, 22 kworker/0:1 queue_delayed_work_on (delayed_work_timer_fn)
+ 1, 0, 22 kworker/0:1 e1000_watchdog_task (e1000_watchdog)
+8842 total events, 2025.658 events/sec
+
+The first comma-separated columns represent the number of events (one
+column per present core), the next column the pid, and the next one is the
+name of the process. The last column shows the function which
initialized the timer and in parenthesis the callback function which was
executed on expiry.
diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c
index 1fb08f2..53d1544 100644
--- a/kernel/time/timer_stats.c
+++ b/kernel/time/timer_stats.c
@@ -67,7 +67,7 @@ struct entry {
/*
* Number of timeout events:
*/
- unsigned long count;
+ unsigned long count[NR_CPUS];
unsigned int timer_flag;
/*
@@ -203,7 +203,7 @@ static struct entry *tstat_lookup(struct entry *entry, char *comm)
curr = alloc_entry();
if (curr) {
*curr = *entry;
- curr->count = 0;
+ memset(curr->count, 0, sizeof(curr->count));
curr->next = NULL;
memcpy(curr->comm, comm, TASK_COMM_LEN);
@@ -259,7 +259,7 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
entry = tstat_lookup(&input, comm);
if (likely(entry))
- entry->count++;
+ entry->count[raw_smp_processor_id()]++;
else
atomic_inc(&overflow_count);
@@ -284,7 +284,7 @@ static int tstats_show(struct seq_file *m, void *v)
unsigned long ms;
long events = 0;
ktime_t time;
- int i;
+ int i, cpu;
mutex_lock(&show_mutex);
/*
@@ -307,19 +307,21 @@ static int tstats_show(struct seq_file *m, void *v)
for (i = 0; i < nr_entries; i++) {
entry = entries + i;
if (entry->timer_flag & TIMER_STATS_FLAG_DEFERRABLE) {
- seq_printf(m, "%4luD, %5d %-16s ",
- entry->count, entry->pid, entry->comm);
+ for_each_present_cpu(cpu)
+ seq_printf(m, "%5luD, ", entry->count[cpu]);
} else {
- seq_printf(m, " %4lu, %5d %-16s ",
- entry->count, entry->pid, entry->comm);
+ for_each_present_cpu(cpu)
+ seq_printf(m, " %5lu, ", entry->count[cpu]);
}
+ seq_printf(m, "%5d %-16s ", entry->pid, entry->comm);
print_name_offset(m, (unsigned long)entry->start_func);
seq_puts(m, " (");
print_name_offset(m, (unsigned long)entry->expire_func);
seq_puts(m, ")\n");
- events += entry->count;
+ for_each_present_cpu(cpu)
+ events += entry->count[cpu];
}
ms += period.tv_sec * 1000;
--
1.8.1.1
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